Question

1. what is 77°f in kelvin? *

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318 k
288 k
308 k
298 k

1. convert 300 k to rankine *

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460°r
300°r
760°r
540°r

1. if the absolute pressure is 25 psia and atmospheric pressure is 14.7 psia, what is the gauge pressure?

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25 psig
39.7 psig
10.3 psig
14.7 psig

Explanation:

15. Convert \(77^{\circ}F\) to Kelvin

Step1: Convert \(^{\circ}F\) to \(^{\circ}C\)

The formula to convert Fahrenheit (\(^{\circ}F\)) to Celsius (\(^{\circ}C\)) is \(T_{C}=\frac{5}{9}(T_{F}- 32)\).
Substitute \(T_{F} = 77^{\circ}F\) into the formula:
\(T_{C}=\frac{5}{9}(77 - 32)=\frac{5}{9}\times45 = 25^{\circ}C\)

Step2: Convert \(^{\circ}C\) to \(K\)

The formula to convert Celsius (\(^{\circ}C\)) to Kelvin (\(K\)) is \(T_{K}=T_{C}+273.15\).
Substitute \(T_{C}=25^{\circ}C\) into the formula:
\(T_{K}=25 + 273.15=298.15\approx298K\)

16. Convert \(300K\) to Rankine

The formula to convert Kelvin (\(K\)) to Rankine (\(^{\circ}R\)) is \(T_{R}=\frac{9}{5}T_{K}\).
Substitute \(T_{K} = 300K\) into the formula:
\(T_{R}=\frac{9}{5}\times300=540^{\circ}R\)

17. Calculate gauge pressure

The formula for gauge pressure (\(P_{g}\)) is \(P_{g}=P_{abs}-P_{atm}\), where \(P_{abs}\) is absolute pressure and \(P_{atm}\) is atmospheric pressure.
Given \(P_{abs}=25\ psia\) and \(P_{atm}=14.7\ psia\)
\(P_{g}=25 - 14.7=10.3\ psig\)

Answer:

1. \(298K\)
2. \(540^{\circ}R\)
3. \(10.3\ psig\)